Carburetor



Feb 16, 1932. G M. BlcKNELl.

CARBURETORV 2 Shets-Sheet Original Filed March 3l, 1921 I mi i Feb. 16, 1932. G; M BICKNELL 1,845,392

CARBURETOR Original Filed March 31, 1921 2 Sheets-Sheet 2 /7 @viga Patented Feb..1.6, 1932 UNITED STATES.A

PATENT OFFICE GEORGE MEBICKNELL, OF ST. LOUIS, MISSOURILASSIGNOR TO CARTER CARBURETOR CORPORATION, OF ST. LOUIS, MISSOURI,`A CORPORATION OF DELAWARE CARBURETOR I Original application led March 31, 1921, ScriaI No. 457,247. Divided and this application filed January 19,-1927. S'rial No. 162,007.

`My invention relates to improvements in ca-rbui'etors, and has for its primary object the construction of a carburetor that will give a very rich mixture forstaiting an automobile engine. A mixture that will be composed of enough air and atomized fuel to form a combustible mixture in a `cold cylinder and to permit the regulating of the amount of air admitted to the mixture s'o that the greatest' possible velocity of air will be maintained at the nozzle outlet.

A further object is to construct a carburetor of the plain tube type that will supply a very rich mixture of fuel and air when fully .choked and that controls the amount of air entering the mixture chamber at the restricted opening of the Venturi tube so that the greatest airI velocity when choked, or par* tially-clioked, will be maintained atthe nozzle outlet into the venturi. Y

At the present timepractically all carburetors are equipped with soinedevice for choking or enriching the mixture for use in starting the engineto which the carburetor is attached when the engine is cold. vIn the case of automobile engines, -`these choking devices are usually connectedso that they can beoperated from thg v dash or the instrument board without tliegdriver` leaving his seat,

'the choking devicesibeing used both in start-4 ing and in warmingiup the engine, as a mixture much richer iiifuel is required lwhen the manifold o1' pipe connecting the ca rburetor with the engine cylinders. The high vacuumx in the manifold assists in 'vaporizing the lighter and more volatile parts of fuel and', if the engine does not start promptly with 'tliismethod of choking, it is necessary toopen' and close the choke valve while cranking the motor thus admitting occasional drafts of air to the cylinders iii order to secure a mixture 'ofJ fuel and air that will form. a combustible'.

or explosive mixture as drawing .fuel only into the cylinderswill cause them'to load up or become ooded" witli raw liquid fuel, and

this will make starting much harder as Vwell 'as thinning out the lubricant in the crank case. due to this liquid fuel s eeping past the piston rings, down the cylinder walls, and into t-he crank case.4

lBy' my construction these conditions are practically eliminated as only the main Venturi air passage is closed when the carburetor is fully choked.. T he secondaryairpassage leading from the main inlet to the carburetor` well remains open at all times, and fby my peculiar arrangement of choke, the highest -velocity of the air entering the mixing chainber is maintained at thev end of the secondary Venturi tubeor nozzle s o that the fuel, which passes therefrom, will be thoroughly at- -oinized and thus slugs or gobs of Araw fuel will not be drawn into the cylinders;

This application is a division of my application tiledMaich 31st, 1921, Serial No.

457,247; which has matured into Patent No.

1,630,887 patented May 31, 1927.

I'n the drawings:

A Fig. lis a side elevation of a carburetor i 'embodying my construction;

, Fig.l 2 is an enlarged view of the same with parts broken away and in section;

Fig. 3 is an enlarged. fragment-al View of the acceler atinf 1 r tubes,l choke valve and the lower portion of the venturi;

Fig. 4 is an enlarged cross section taken on the line`4 4 of Fig. 2;

Fig. 5 of Fig. 4; and Fig. 6 is a side'vv'iew. of the accelerating tubes employed.

In the construction of device I employ a housing or casing 7, which has a flange 8 at -its -upper end b v means of which the car buretor is attached to the intake manifold of 'an internal combustion engine..

Integral with the casing 7 is a floathams a Section taken on the line 5 lower end being' provided witha screw ber 9 which is onf ordinary construction "and which is provided with a Strainer 10 having pipe.

a ittting `11 for, the attachment of affuel `15 anda mixing chamber 16. These chambers communicate with each other so that air can passfrom the mainI air inlet into the mixing chamber. Located in the lower end of the mixing chamber is a Venturi tube 17. The upper portion ofthe housing 7 forms the suction chamber 18.v The' suction chamber other` by vmeans of a Vthrottle valve 19. This v.throttle valve is mounted on a Vshaft 2() to the outer end of which is secured a lever 21.

.Secured to the lever 21 is a rod or cable 22.

which leads to the throttle control located at any suitable point. l

Secured in the main air inlet and concentricY with the opening in the Venturi tube -17 is a well 23. This well communicates with the l'oat chamber 9 by means of a passage 24 so that fuel can be supplied to the well. Thef port 27, forming. the passagel for the idling mixture which'supplies fuel to keep the en- ,gine turning when the throttle valve is closed to its idling position. A

Carried by the upper end of the well 23 1s threaded cross 29 thus forming passageways 30 through which air can enter the well.

Secured to the underside of the cross 29 is a bar 31 which has extending therethrough accelerating tubes-32, 33 and 34. As will be noted `from Figs. 2', 5 Iand 6, these tubes all terminate in the same plane above thebar 31 but extend to various depths in the well.

It will also'be noted that the tubes extend into the-secondary Venturi tube 28.

'Surrounding the well and secondary Venturi tubeis the choke valve 35, its upper end converging toward the tube as indicated by the numeral 36. This converging pa'rt is preferably conical as a' finer adjustment can be obtained'by this shape although, if found desirable, I may Vary the shape of the upper end.

Integral with the converging ,portion 36 is a downwardly extending sleeve 37. This sleeve fits snugly around the outer portion of the secondaryVenturi'tube but is not tight enough to bind thereon so that the choke valve can be freely moved up and down. It willbe noted from Figs. 2,3 and 6 that the inside diameter of the valve 35 is -larger than the well 23 so'` as to form a passageway 38 completely around the well. This permits air t0 pass V`upward through the lpassageway 38,

-remain open at all times.

down through the passages 30 into the well 'cut on the choke valve 35. Secured to thfe outer end of the shaft 39 is a leverl 42 to which is attached a rod or cable 43 by means of which the choke valve can be raised and lowered. AThis rod also extends to a suitable place for operation, the same as the rod 22. and mixing chamber are separated-from each The operation of my device is as follows: After the carburetor has been properly installed and adjusted when'it is desired to start the engine, the throttle valve 19.is slightly open and the choke valve 35 is closed. By moving the lever 42 so that the upper portion 36 ofthe chokevalve will contact with the Venturi tube17 air is prevented from passing directly from the main air inlet into the venturi.

The suction caused by cranking the engine immediately starts a How of fuel and air through l.the second Venturi tube .28, the air entering the well through the passages 38 and 30 as shown in Fig. 5. These passages This air mixes with the fuel which is drawn from the well through theaccelerating tubes 31, 32 and 33 causing a spray of fuel and air to pass through the mixing chamber into the manifold and cylinders. It will be noted that even when the carburetor is fully choked a mix- -ture of fuel and air will always be drawn lowered, the upper end 36 of the choke valve gradually leaves the reduced portion of the Venturi tube 17 permitting air to pass from the main air inlet 15 between the reduced portion of the Venturi tube and the tapered portion of the choke valve. This air will pass upward .and around the upper portion ofthe choke valve in such a manner that its highest point of velocity is near the upper end ofthe choke valve. i

i The operation of the accelerating tubes is as follows: When not in action the fuel level in the carburetor well will be near the upperends of the accelerating tubes. When the engine. is idling this level will be slightly lowered by the iow of fuel through the idling tube, As soon as the throttle is opened causing enough su'tion to be applied to the acceleratingl tubes to lift fuel therefrom, the

level in'the well will be further lowered until it reaches the lower end of the tube 32. Air will then lbe admitted, which unites with the fuel causing a spray of fuel and a-ir to be delivered into the secondary venturi from the and is drawn into the secondary venturi 28,

passes the upper ends of the accelerating tubes and assists in raising the fuel in the Well through these tubes and in breaking. this fuel up into fine particles in which state it can be easily carried by the air stream into the cylinder. f When the throttle. is closed and only the idle `jet in action fuel flowing past the needle valve 25 rapidly refills the Well.

In the ordinary type of carburetors Where the choke valve is in the'main air inlet, ,the highest point of velocity was -around the choke valveand not around the nozzle. This permitted slugs or gobs of lliquid fuel. to bedrawn up, which were'too heavy to be carried into the cylinder and, consequently, settled on the sides of the manifold and ran down, and if several gobs or slugs of raw, fuel in succession found their way into a cylinder, that cylinder would become, what is termed, flooded.. In other words, there was more fuel in thecylinder than could be properly ignited and consequently it was impossible 'to start the engine until this fuel had evaporated or drained from the cylinder iii sufficient quantity to ermit an explosive mixture to vbe formed W en the engine was againcranked.

By my construction of carburetor the fuel as it issuesfrom the main nozzle is thoroughly atomized so that what may be'termed a v et gas is delivered to the cylinder when the choke is fully closed but no gobs or slugs of fuel will be delivered, because thehigh velocityV of the air at the discharge or upper end of the secondary venturi is suflicient to break the slugs or gobs up and atomize them so that therewill be nov danger of flooding the cylinders. f Itlwill Aalso'be noted that when the Achoke valve, in my structure, is fully closed there is always a certain"v amount of air admitted, which `ivi-ll mix with and atomize the fuel because of my construction the entire suction istnot placed on the fuel supply as is the case where a butterfly valve is used in the main air inlet. Consequently there is very little danger of choking or flooding the enginewith raw fuel when the choke is vfully pulled out or closed, and furthermore by my construction as the choke valve'is gradually opened,

the lgreatestsuction possible created by theA velocity of tlie'airpassing through the Venturi tube is at the discharge end 'of the secondary venturi and not around 'the edges of4 I claim is 1. A carburetor comprising a casing hav- `ing va main air passage therein, a mixing chamber communicating with said main air passage, a Venturi tube located in the mixing chamber, a nozzle for supplying both fuel and air carried by said casing and terminating near the point of greatest constriction in the Venturi tube, a manually operated means having a conical upper end whereby the passage of air from the main air passage through said point of greatest constriction can be regulated and maintained constantv for a predetermined lengt-li of time whereby the highest velocity of air passing from said main air inlet to the mixing chamber is maintained adjacent the endof, the nozzle, and a throttle valve located above'said Venturi tube. y

2. A carburetor comprising a casing having a main air passage therein` a mixing chamber communicating with said mainair passage, a Venturi tube located in the mixing chamber, a throttle valve located beyond the delivery end of saidVenturi tube, a secondary Venturi tube for supplying both fuel and air carried by said casing and terminat-l ing near the point of greatest constriction in the Venturi tube, and manually operated means Wherebythe passage of air from the main air passage through said point of greatest constriction can be fixed andregulated so that the highest velocity of air passing from said main air inlet to the mixing chamber is maintained adjacent the endof the secondary Venturi tube without varying the amount of fuel normally delivered to said second venturi.

3. A carburetor comprising a casing having a main air chamber, a mixing chamber in said casing communicating with said I nain air passage, a. Venturi tube located within said mixing chamber, a well carried by said casing, means for predetermining the deliving a main air passage, a mixing chamber communicating therewith, a Venturi Atube located in saidmixing chamber, a well carried by said casing, mea-ns for feeding a constant amount of fuel to saidwell, a nozzle carried by said well and havingits upper end terminating adjacent the point of greatest constriction of theA Venturi tube, a conical choke valve surrounding said nozzle, manually.. operated means for raising and lowering'and retaining said choke valve in position, the upper end of said choke valve being adapted to enter theVenturi tube for opening and closing its communication with the main air inlet whereby the highest velocity of air passing into the mixing chamber is maintained at the point of fuel delivery therein, and a valvefor controllin the amount of air and fuel drawn from-sai mixing chamber. A, y

5. In a carburetor "a main air' passage, a mixing chamber, a throttle valve in said mixing chamber, a Venturi. tube below said throttle valve for connectin themain air passage to the mixing cham er,4 a well below said Venturi tube, an auxiliary passage ,including a second Venturi tube communicating' with the well and first mentioned .Venturi tube and arranged to convey air downward-l ly into said well and upwardly in said second Venturi tube,` and. means' surroundingsaid second Venturi tube for closing and regulating the size of the'opening in the first mentioned Venturi tube without changing the size of the -auxiliary passage.

6. Acarburetor comprisinga housing, a main air, passage formed in said housing, an auxiliary passage communicating with said main air passage, means including a fuel well having an air vent and a plurallty of vertically Vspaced discharge. outlets feeding' a mixture of air and fuelthrough-said auxiliary' passage tolsaid main air passage, manually' operated means for controlling the capacity ,of the main air passage, said means being stream lined to provide a gradual increaseand decrease of air velocity, the point of com- 'munication of said auxiliary passage with saidmain passage beinglsubstantially at the' point -of highestvelocity of the air flowing through said passage. v

7. A carburetor comprising4 afhousing, a main air passage formed in said housing, a throttle valve .and-a choke valve in said'pas-` sage, a venturi in said passage adjacent said choke valve, means including a fuel well hav- 8.- In a carburetor, a fuel mixing conduit i comprising a main passageway having an inlet` and anvoutlet, a throttle valve controlling said outlet, a venturi formed in said passageway, a' fuel chamber, an' auxiliary passageway adapted to receive-fuel from said chamber, said chamber having an air vent near the upper part thereof, fmeans comprlsing a constant level supply chamber and a calibrated passage way for supplying fuel to said fuel chamber, a second venturi in said auxiliary passageway, said second venturi having an air inlet and a discharge outlet substantially concentric with first-named venturi and terminating at the throat thereof, and a manually operable choke valve slidably mounted in concentric relation with the firstnamed venturi and surrounding the discharge outlet ofthe second venturi.

9. In a carburetor, a fuel mixing conduit comprising a main passageway having an inlet and an outlet, a throttle valve controlling saidoutlet, a venturi formed in said passageway to gradually increase and decrease the velocity ofthe iuid passing therethrough,

a fuel chamber an auxiliary passageway adapted to receive fuel from said chamber, a

ventlri in said passageway, a; plurality of f vertically spaced air inlets for said venturi, said' venturi 'having a discharge outlet substantially concentric with said 'first-named venturi and terminating'at the throat thereof,'and a manually operable choke valve'slidl ably mounted in concentric relation with the first-named venturi and surrounding the discharge outlet of the second venturi, said choke valve tapering inwardly and toward the discharge outlet of theauxiliary venturi whereby a fluid stream is directed toward said auxiliary discharge outlet at high velocity. A

10. lIn a carburetor, a fuel mixingA conduit j l comprising a main air passageway having a venturi therein, an auxiliaryA air and fuel passageway concentric with saidventuri and discharging'substantial'lyat the throat thereof, a choke valve slidably mounted on said Aauxiliary conduit, said choke valve having a tapered endfor regulating or closing the venturi, the inner wall'of said choke valve being adapted' to lextend beyond the end ofjthe auxiliary passageway when't the choke valve 7.

is clbed, and the outer (wall of said choke f valve rbeing adapted to direct a .stream of alr at high velocity into contact-withthe airv and means for varying the velocity of the airl and fluid discharged from theauxiliary passageway.

p 11. In a carburetor, means for forming an emulsion of liquid fuel and air; said emulsion forming means comprisin a, fuel well having. an air vent, one or more ,dgischarge out-V lets, at least one of said outlets Abeing below the normal liquid fuel level, and a calibrated fuel inlet, means including a venturi for mixing additional air with the emulsion to form a spray of liquid fuel and air; means comprising a venturi for mixing additional air with said spray to produce a final mixture;

mixed with said spray at the mixing point.

12, In a carburetor, means for forming an emulsion of liquid fuel and air; said emulsion forming means-comprising a .fuel Well .having'an air vent, one or more discharge outlets, at least one of said outlets being below the normal liquid fuel level, and a callbrated fuel inlet; means including a venturi-for mixing additional air with the emulsion to form a spray of liquid fuel and air; means comprising a venturi for mixing additionalair with said spray to produce afinal mixture; and means for varying the velocity of the air mixed with said spray at the mixing point; and means posterior .to said mixing point for controlling'the flow of mixturer through the carburetor.

13. In a. carburetor, means for forming'- an emulsion of llquld and air ,said emulsion forming means comprising a fuel well having an least one of said outlets being below the norair vent, one or more discharge outlets, at

mal liquid fuel level, and a calibrated fuel inlet; means for mixing additional air with conduit and said well being supplied with fuel other.` y i i In testimony whereof I have affixed my lsignatur-ef if '.GEORGE M. BICKNELL through a common calibrated. passageway.; said passageway tending 'to restrict'said fuel supply, whereby the operation of either the well or the low speed'fuel supply will tend to restrict the 'discharge of fuel from the l 

